Power Conversion Module for Use With Optical Energy Transfer and Conversion System

ABSTRACT

A power conversion module for use with optical energy transfer and conversion system has a hemi-spherically configured housing, an array of photovoltaic chips mounted on the interior thereof, and inlet and outlet ports connected thereto. An end plate connected to the housing defines a cavity. An actively cooled high-power connector has one end connected to a fiber optic cable and the opposite end traversing the end plate and extending within the cavity. Beam forming optics within the cavity are in optical communication with the connector to disburse received optical energy in a hemispherical emission pattern of uniform flux toward an array of photovoltaic chips mounted in complementary configuration to the housing within the cavity, each chip spaced equidistantly from the beam forming optics. A heat sink within the housing has a plurality of fluid channels therethrough through which a work fluid removes heat via the outlet port. In alternative embodiments, the power conversion module includes a housing having a spherical configuration and a plurality of power conversion modules.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional application claiming priority to and the benefit ofU.S. application Ser. No. 14/292,495, filed May 30, 2014, and entitled“Power Conversion Module for Use With Optical Energy Transfer andConversion System,” which claims priority to and the benefit of U.S.provisional application Ser. No. 61/860,702, filed Jul. 31, 2013, andentitled “Non-Line-of-Sight Remote Optical Power Conversion,” which isincorporated by reference herein.

U.S. application Ser. No. 13/303,449, filed Nov. 23, 2011 and entitled“Optical Energy Transfer and Conversion System,” is incorporated byreference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with Government support under Grant No.NNX10AE29G awarded by NASA. The Government has certain rights in thisinvention.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to power systems. More specifically, thepresent invention is an improved beam dump for use in a system thattransfers optical energy to a remote location and subsequent conversionof the transferred optical energy to another form of energy such asheat, electricity, or mechanical work.

2. Description of the Related Art

U.S. application Ser. No. 13/303,449 (the '449 Application) describesthe development of an integrated collection of systems that enable thetransmission and effective end-use of very large amounts of opticalpower (kilowatts to tens of megawatts) over relatively long distances(from a kilometer to as much as one-hundred kilometers or more) tofixed, movable, or mobile platforms operating on the ground, undersea,under ice, in the air, in space, and on other planets. The concept isinherently non-line-of-sight, which allows it to directly bypass severeproblems that have plagued efforts to utilize laser power beaming overlarge distances through the atmosphere, underwater, and over terrainwhere the receiver is not within view of the optical power source.

The '449 Application previously disclosed, inter alia, a ground-based(or base-of-operations-based) power supply with a chilling system usedto provide sufficient electrical power and appropriate coolant to a highpower fiber laser directing power into an optical fiber. For thepurposes of this discussion “laser power” and “optical power” are usedinterchangeably to refer to any wavelength of electromagnetic radiationthat can be effectively injected into a small diameter fiber (generallyless than one millimeter in diameter, but potentially larger) that isfabricated from a material that is optically transparent at the selectedwavelength.

One aspect of the '449 Application is power re-conversion to electricityand mechanical power at the far end of the fiber. In several casesdescribed in the '449 Application, a “beam dump” is used where theoptical energy carried by the fiber is expanded into a diffuse,divergent or collimated broad beam, and caused to impinge directly orindirectly on a thermal mass capable of withstanding the intense heatthat will be produced. The beam dump can be advantageously fabricatedfrom a high temperature refractory material, e.g., beryllium oxide (BeO)or similar material, but can also, with careful design and heat removalmethods, be made to work with common materials such as aluminum, copper,or steel.

In one variation, the beam dump is surrounded by a plurality ofthermoelectric conversion (TEC) chip arrays that convert heat directlyto electricity on the basis of thermal difference between the core ofthe beam dump and its exterior environment. This approach isparticularly effective for polar regions and planetary roboticsoperations where external ambient temperatures can be extremely low. Inanother variation, the expanded laser beam energy impinges directly ontoan advantageously tuned-wavelength photovoltaic array (or anygeneralized array of devices that respond to light within the vicinityof the laser wavelength and directly produce electricity) that convertslight directly to electricity. In yet a third variation, the beam dumpis used directly as the heat source for a heat engine, e.g., a Stirlingcycle engine, from which mechanical power can be directly extracted andelectrical power can be secondarily generated at the remote mobilityplatform. All of these power conversion systems can produce electricitythat can be directly consumed by a remote mobility platform (orstationary sensing, communications or power transfer platform), used torun its onboard electronics, heaters, sensors, actuators, electricmotors and other “hotel” and mobility energy needs and, as well, torecharge a regenerable onboard local power supply, as for example, ahigh energy lithium-ion battery, a hydrogen-oxygen fuel cell or thelike.

While the raw (coherent) optical power of a focused laser beam hascertain utility at remote locations, the conversion of that opticalpower to electrical power has very broad application. Specifically, theefficient conversion of photons to electrical power enables the directand immediate use of common (and existing) remote machinery that hasbeen designed to operate (or could be made to operate) on electricalpower. The most immediate example is that of remotely operated(underwater) vehicles (ROVs) and autonomous underwater vehicles (AUVs).Both are used extensively in the petroleum industry for underwaterconstruction, assembly, maintenance, and inspection. In the specificcase of ROVs, which are the workhorse of offshore oil production today,these are currently limited in their utility and cost effectiveness bythe requirement of being chained by a heavy, bulky electrical powertether to an overhead ship or other floating platform. As the operatingdepth (or horizontal distance from a power supply) of an ROV increases,the supply voltage in the tether must be increased to compensate forresistance losses. The cable cross section, and its required thicknessof insulation to prevent arc-over, increase proportionately until thecable weight and the drag forces on the cable produced by ocean currentscan only be handled by large, expensive sea vessels.

FIG. 8 of the '449 Application shows the photon flux being transportedto a beam dump housing by fiber. Inside the beam dump, the beam isexpanded, shaped and optionally collimated by beam-forming optics. Theexpanded beam then impinges on the photovoltaic (PV) array for directgeneration of electrical power. Because only a portion of the photonswill be converted to useful electrical current by the PV array, the restgo into heating the beam dump. That excess heat generates additionalelectrical power, such as by using a cylindrical array of thermoelectricconverter (TEC) chips mounted against the inside wall of the beam dump.The beam dump contains within its structure an efficient heat exchanger(shown as coils through which a conducting fluid could pass to removeheat, but which equally well could be done by other means such as heatpipes and the like) for the purpose of cooling the back side of the TECchip array to provide the temperature differential needed by the TECarray to generate electricity, as the level of current produced isproportional to the temperature differential across the TEC array.

But the power conversion design disclosed in FIG. 8 of the '449Application is inefficient on several counts. The present inventionaddresses some of these inefficiencies in a manner that provides, interalia, practically-implementable sub-sea power converters for theoperation of such industrial devices as ROVs, AUVs, and permanentsub-sea power distribution, communications, and instrumentation stationsand bases for ROVs and AUVs.

Optical power delivery requires that the photon flux (power) densityreaches extremely high levels within the optical carrier. As of 2009,power densities exceeding two terawatts per square centimeter (2 TW/cm²)had been achieved. In contrast, the allowable sustained photon flux on awavelength-optimized photovoltaic (PV) chip is currently about ten wattsper square centimeter (10 W/cm²), which is about two-hundred billiontimes less than the source flux (higher flux tolerances of up to fivehundred W/cm² are reported for sunlight concentrators, but this is stillfour billion times less than the peak laser flux).

The interest in using photovoltaics for power conversion of a photonstream is obvious: Direct conversion of photons to electrons withefficiencies as high as forty-two percent (42%) are possible in currentlaboratory grade PV chips, and this number is expected to climb in thecoming years. As such, there is great motivation to get as much of thepower converted directly before resorting to secondary methods thatutilize waste energy (mainly heat) for power generation. Approaches havebeen developed to do this on a small scale (i.e., milliwatts), but noneto date have attempted to deal with the substantial problem ofconverting kilowatts to megawatts for industrial grade remote powerutilization where a high energy laser is the power source.

Another factor in the design of a remote photon-powered electricalgenerator is that of temperature sensitivity of the various powerconversion devices. Currently-available PV chips are temperaturesensitive with output efficiency decreasing with increasing temperature.Peak output efficiency usually occurs around zero degrees Celsius (0°C.) with limiting (i.e., destructive) temperatures in excess of onehundred degrees Celsius (100° C.).

Conversely, a TEC chip only begins to see its highest conversionefficiency at high differential temperatures. Generally, minimum TECdifferential operating temperatures start at twenty-five degrees Celsius(25° C.) and reach peak efficiency at greater than a temperaturedifference of two hundred degrees Celsius (200° C.). Even at the highend of this scale, however, conversion efficiency is only on the orderof five percent. Contrasting this, a well-designed heat engine (e.g., afree piston Beta-type Stirling engine) can achieve better thanthirty-seven percent (37%) conversion of thermal (heat) energy toelectrical energy using helium working fluid and linear alternators forthe conversion from mechanical action to electricity.

These factors place significant design constraints on possible solutionsfor highly-efficient conversion of high energy optical power toelectrical power at a remote industrial vehicle or industrial machine.

The present invention uses a tightly integrated “mixed-mode” powerconverter “cluster” system that receives optical power from a remotelaser and converts that in stages to electrical energy. Under idealconditions the following “mixed-mode” power generator can be constructedas illustrated in the table below:

TABLE 1 Four-Stage Mixed-Mode High Energy Optical Power ConverterPrimary Percentage optical Conversion Power input ultimately Step MethodSource converted to electricity 1 Photovoltaic Mono-wavelength 42 light2 TEC Waste heat 2.9 3 Primary Stirling Waste heat 20.7 Generator 4Secondary Stirling Waste heat 12.9 Generator Total Electrical 78.5Conversion Efficiency

As shown in Table 1, for every optical Watt of power that reaches thebeam dump, forty-two percent (42%) can be converted directly toelectrical power by a properly constructed photovoltaic array. The wasteheat can be used to drive a TEC thermoelectric generator, which canrecover an additional 2.9% of the initial power. If the remaining wasteheat is piped (using insulated isothermal transfer systems) to a highefficiency Stirling generator (or similarly efficient heat engine), then20.7% of the initial optical power can be converted to electricity. Ifthe output from the hot stage of the first Stirling generator iscascaded to a second unit, then an additional 12.9% power conversion canbe achieved, and so on. If a system only has the four stages depicted inTable 1, 78.5% of the initial Watt of input optical power that reachesthe beam dump will be converted to electricity. Designing thiscapability into a compact, manufacturable device that can work in deepwater is one objective of the invention described herein. A simplifiedsystem that captures most of the energy would utilize only Steps 1 and 3in the above table.

The sequence shown above is the most efficient way to collect andconvert the power. If one-hundred percent (100%) PV conversionefficiencies could be achieved then the remaining power conversion stepscould be eliminated. Thus, another objective of the present invention isto maximize the PV conversion of the optical energy during the firststage of the system.

TEC power conversion operates best at locations where very high thermalgradients exist. In the laser beam dump scenario described here, thehighest thermal gradients will be immediately adjacent the beam dump.Thus, locating a TEC generator array elsewhere would be inefficient.Although Stirling generators also prefer high temperature gradients,they can operate efficiently at lower temperatures and lower temperaturegradients.

“Heat exchanger,” as used herein, refers to any method of capturing,extracting and transferring of heat from one location (e.g., the core ofthe beam dump) to a different location (e.g., a Stirling engine adjacentto the beam dump) such that maximum electrical energy can be derivedfrom the photonic energy delivered to the beam dump.

BRIEF SUMMARY OF THE INVENTION

The present invention is a power conversion system for convertingoptical energy received from a fiber optic line to electrical energy.The system comprises a housing having at least one interior surface,said at least one interior surface defining an interior space withinsaid housing; a high power connector having a first end and a secondend, said first end coupled to the fiber optic line, and the second endpositioned within the interior space; beam-forming optics within theinterior space positioned proximal to the second end of the saidconnector, said beam-forming optics having a focal plane; an end arrayhaving a first plurality of PV chips, said first plurality of PV chipsin a partially-spherical arrangement spaced a first radial distance fromsaid beam forming optics; at least one annular array having a secondplurality of PV chips, said second plurality of PV chips in an annulararrangement, said at least one annular array longitudinally positionedbetween said end array and said beam forming optics; and wherein each PVchip of said first and second pluralities of PV chips comprises alight-receiving surface having a normal vector intersecting the focalplane of said beam-forming optics.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a partial sectional view of one embodiment of the presentinvention.

FIG. 2 is a partial sectional view of a second embodiment.

FIGS. 3-4 show several possible geometric orientations for thearrangement of currently manufactured PV chips for use in the end-facepower generation surface that lines the direct end-face target for theexpanded photon beam in a cylindrical beam dump core.

FIGS. 5-6 show a modified solid model cross section of a cylindricalbeam dump showing the addition of the annular power generation PV rings.

FIG. 7 shows a plot of an ideal beam profile for a cylindrical beam dumpwith radial PV arrays, such as the embodiments shown in FIGS. 1-2.

FIG. 8 shows a schematic of a vehicle power control system based solelyon a PV array being used to generate electricity.

FIG. 9 is a partial section view of an alternative embodiment of theinvention.

FIG. 10 is a partial section view of another alternative embodiment ofthe invention.

FIG. 11 is a partial section view of still another alternativeembodiment of the invention.

FIG. 12 is a system view of multiple spherical arrays opticallyconnected to the same fiber optic line.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a single-stage photovoltaic (PV) power conversion beam dumpor module 20 designed for deep water use. The module 20 has a generallycylindrical high pressure housing 22 comprising a housing body 24 and apressure end plate 26 that can be removed for service access to theinterior of the module 20. The housing body 24 has an interiorcylindrical surface 28 adjacent to a closed end surface 30 that definesa first cavity having a closed end and an open end. The first cavity isformed around a centerline 32 that extends through the module 20. Theend plate 26 includes a partially-conical interior surface 34 thatdefines a generally conical second cavity opening toward and adjacent tothe first cavity. The second cavity is formed around the centerline 32,and together with the first cavity defines the interior of the module20. A photon source (not shown) is connected to end plate 26 via fiberoptic line 36. A flat or partially-spherical PV end array 38 is locatedwithin and proximal to the closed end surface 30 of the first cavity.Annular PV arrays 40 a-f are spaced within the first cavity between theend array 38 and the beam forming optics 42. Beam-forming optics 42direct optical energy received from the photon source toward the arrays38, 40 a-f.

FIG. 2 shows a different embodiment 52 than that shown in FIG. 1, butwith many of the same elements, which are identified by the samereference numbers. This second embodiment 52 includes a flat end plate26′. Beam forming optics 42 are fixed to a mount 54 attached to andextending into the cavity from the end plate 26′.

In the second embodiment 52, the fiber optic line 36 is coupled to theend plate 26′ at a first end of a high power connector 44 that includesa water-cooling inlet port 46 and outlet port 48 that completes a fluidcirculation path cooling the high power connector 44 during use. Thesecond end of the high power connector 44 is positioned within thecavity proximal to the beam forming optics 42. The beam forming optics42 can be multi-stage standard optic and Fresnel optics, with andwithout uniform and non-linearly applied anti-reflective,wavelength-specific coatings. The beaming-forming optics 42 have a focalplane 43 that serves to widen and disperse the beam into a broad patternthat impinges on each of the arrays 38, 40 a-f.

FIGS. 3-4 show two typical configurations—a radial design 54 and arectilinear design 56—for the annular PV arrays 40 a-f shown in FIG. 2.Each design 54, 56 contemplates fabrication using standard fifteenmillimeter square PV chips 58, with an objective to create the greatestPV exposure area on each annular ring while using commonly available PVchips. Alternatively, a custom full PV coverage array could also befabricated. Existing PV chips frequently have a square geometry with aflat light-receiving surface with a characteristic edge dimension on theorder of fifteen millimeters, although custom chips of almost any shapecan be fabricated.

FIGS. 5-6 depict the same approach to rectilinear and radial topologies60, 62, respectively, for the partially-spherical PV end array 38 ofFIGS. 1-2. Further, in practical implementation, the PV end array 38 canalso be flat without significant power generation loss. FIGS. 3-6 showbest case realizations of advantageous PV array geometries usingcurrently available PV chip production methods. It may be appreciatedthat completely filled geometries representing the annuli of FIGS. 3-4and the disks of FIGS. 5-6 may be one day manufacturable.

Referring back to FIG. 2, the annular arrays 40 a-f are located atradial distances D1-D6, respectively, from the focal plane 43 of beamforming optics 42 and are oriented at angles α1-α6 relative to thecenterline 32. In other words, the PV chips composing the arrays 40 a-fface the focal plane 43. The end array 38 is located at a radialdistance D7 from the focal plane 43 such that the annular arrays 40 a-fare positioned longitudinally between the end array 38 and the beamforming optics 42. As used herein, the “angle” of the array refers tothe angle of a vector normal to the PV chips light-receiving surfacecomposing the array relative to the centerline. Similarly, a PV chip“faces” a direction or element when the normal vector is parallel to thedirection and intersects the element. In an alternative embodiment, thePV chips composing of the arrays 40 a-f face back toward the end array38.

The annular PV arrays 40 a-f triple the available photovoltaic arearelative to a module otherwise only equipped with an end array 38. Thesurface area can be further expanded by hypothetically lengthening themodule 52 and cavity along centerline 32 while maintaining the sameinternal diameter as shown in FIG. 2 and adding more PV annular arraysalong the length of the cavity. As the PV annular arrays are placedfurther from the beam forming optics 42, the power received per unitsurface area will decrease proportional to 1/R², where R is the radialdistance (e.g., D1-D7) from the beam forming optics 42.

To maintain a uniform flux on each PV array, which is essential tomaximize the efficiency per unit volume of the power conversion module,the beam forming optics 42 are designed to generate a beam profilesimilar to that shown in FIG. 7. This beam profile has an arbitrarystarting off-axis angle that is symmetrical about a centerline and isdefined by the flux received at the first annular PV array 40 a. Thus,for the first PV array 40 a in FIG. 2, the off-axis angle isapproximately fifty-five degrees (and its mirror, −55 degrees). The beamforming optics 42 confine light to within this angular range and theflux is zero outside this range. The flux being received at the first PVarray 40 a is arbitrarily set to be 100 W/cm². The flux at the secondthrough sixth arrays 40 b-f and the end array 38 must increase toaccommodate the increased radius from the beam forming optics 42. Therate of flux increase needed to maintain uniform flux per unit of PVsurface area is proportional to the radius of each annular array untilthe end array 38 is reached.

FIG. 7 depicts a flux of 650 Watts/cm², which is arbitrary forillustrative purposes. The profile shown in FIG. 7 can be obtainedthrough proper optical design using both continuous (glass) optics aswell as Fresnel ring optics. The latter approach (Fresnel) can be usedto create step-wise increases in photon flux that could match thediscrete spacing of the annular PV rings 40 a-f shown in FIGS. 1-2.

FIG. 8 shows a schematic of a vehicle power control system based solelyon a PV array being used to generate electricity. Photons 64 arrivingvia fiber optic line 36 are caused by beam forming optics 42 to impingeon the PV arrays 38, 40 a-f. The arrays 38, 40 a-f are designed toprovide optimal battery-charging voltage 72 to an onboard batterycomprising battery electronic control systems 66 and battery cells 68. ADC-to-DC power converter 70 converts the bus voltage 72 to anappropriate level for use by system load 74. The system load 74 could beany power consumer performing useful work at the receiving end of theoptical power, including but not limited to operation of vehiclemobility systems, vehicle electronics, remote instruments and actuatorsas well as recharge systems for vehicles and systems that can dock tothe power conversion system, etc. . . . The battery sub-systems 66, 68provide a buffer for the overall electrical operation of the vehicle inthe event of a momentary cessation of optical power, i.e., photons 64.

FIG. 9 shows an alternative embodiment 100 having a housing assembly 102with a hemispherical geometry on both ends. The embodiment 100 isgenerally cylindrical and symmetrical about a longitudinal axis 104. Thehousing assembly 102 comprises a main housing 106 connected to an endhousing 108. The main housing 106 is generally cylindrical with a closedhemispherical end 110 and an open end 112. The main housing 106 has aclosed partially-spherical end 116, though a flat ended configurationwould also suffice with close to the same efficiency, and an open end118 coterminal with the open end 112 of the main housing 106.

Still referring to FIG. 9, the annular PV arrays 40 a-e are mounted to aheat sink 127 which may be fabricated out of any material that is aconductor, including ceramics (e.g., beryllium oxide), metals (e.g.,silver, copper, or aluminum), and carbon (including formed componentsusing diamond powder, short carbon fibers, and grapheme). The PV arrays40 a-e are mounted on the interior surface of the heat sink 127 usingthermally conducting compounds, generally consisting of grease basecompositions of ceramic powders (e.g., beryllium oxide, aluminumnitride, aluminum oxide, zinc oxide or silicon dioxide), solid metalparticles (e.g. silver or aluminum), or carbon (diamond powder, shortcarbon fibers, or graphene). An array of thermoelectric convertor (TEC)chips 128 is optionally mounted to the exterior side of the heat sink127 to sense the hot side of the beam dump or module 100.

A ceramic main heat sink 120 occupies the main housing 106 and is formedaround a generally-cylindrical cavity 122 having a partially-sphericalclosed end 123 and an open end 124. The partially-spherical closed end123 can also be in a flat configuration with minimal loss of powerconversion capability. The heat sink 120 is formed of beryllium oxide,but may alternatively be fabricated from any material that is aconductor, including other ceramics, metals, and carbon based materials.A number of first fluid channels 126 extend around and through the mainheat sink 120. A number of TEC chips 128 are positioned adjacent to themain heat sink 120 and the boundary of the cavity 122.

The end housing 108 is hemispherical with an open end 130 and has achannel 132 extending to the open end 130 around the longitudinal axis104. The end housing 108 includes a fluid inlet 134 and a fluid outlet136 connected to pipe segments 138, 140, respectively.

A second heat sink 142 occupies the end housing 108. A number of secondfluid channels 144 extend around and through the second heat sink 142.The first and second fluid channels 126, 144 form fluid communicationspaths that extend within the main heat sink 120, within the second heatsink 142, and between the main and second heat sinks 120, 142. Thesecond fluid channels 144 are also in fluid communication with the fluidinlet 134 and fluid outlet 136.

Seals 146 are interposed between the main housing 106 and end housing108. The end housing 108 closes the cavity 122, which contains apartially-spherical photovoltaic array 38 proximal to the closed end 123and a number of annular photovoltaic arrays 40 a-e positionedlongitudinally between the array 38 and the end housing 108. Eachannular array 40 a-e is oriented to face beam forming optics 42positioned in the cavity 122 between the annular arrays 40 a-e and theseals 146. The beam forming optics 42 are configured to direct equalamounts of optical energy to each array 38, 40 a-e while considering thedistance of each respective array from the focal plane, as describedwith reference to FIG. 7.

A high power connector 148 is positioned in the channel 132 andconnected at one end 150 to a fiber optic line 152. A second, opposingend 154 of the connector 148 is positioned in the cavity 122 andoriented to direct optical energy toward the beam forming optics 42. Theconnector 148 includes an inlet port 156 and an outlet port 158 in fluidcommunication with a pump (not shown) for the purpose of providingthermal control of the connector 148 and the beam forming optics 42.

As described with reference to FIGS. 1-8, optical power is delivered tothe embodiment 100 via the fiber optic line 152, and is emitted from thesecond end connector 154 toward beam forming optics 42, which expand thebeam and cause it to impinge on the annular PV arrays 40 a-e andpartially-spherical PV end array 38 with a uniform flux at each array.As they are impinged by optical energy, the arrays 38, 40 a-e convert aportion of the optical energy to electricity. Waste heat is transferredto the heat sink 120. A working fluid circulating through the channels126, 144 transfers heat to a work object or a heat engine (e.g., aStirling engine) via pipe segment 140 which removes the heat from theheat sinks 120, 142 and uses the heat to perform work and/or generateadditional electrical power.

FIG. 9 is illustrative of a three-stage power conversion system whereoptical power is converted to electric power via PV arrays 40 a-e,mounted on heat sink 127. The excess heat is then transferred via pipesegment 140 to a Stirling engine (not shown) which converts the heat toelectrical power. Any excess heat can then be transferred to a secondStirling engine (not shown) which then converts the heat to electricalpower.

FIG. 10 shows yet another embodiment 200 that comprises a generallyhemispherical housing 202 symmetrical about an axis 204. The housingincludes an inlet port 206 and an outlet port 208 connected to first andsecond pipe segments 210, 212, respectively. The housing 202 is formedaround a beryllium oxide or similarly effective heat sink 214, whichdefines a hemispherical cavity 216. Heat sink 214 advantageously hasmaterial properties that would allow the structure defined by 200 toresist failure under any external hydrostatic pressure in a realisticworking environment (e.g., full ocean depth on Earth). Fluid channels218 run through the heat sink 214 and form a fluid communication pathbetween the inlet and outlet ports 206, 208. A generally-hemisphericalarray of photovoltaic chips 222 is mounted proximal to the boundary ofthe cavity 216 and the heat sink 214.

The housing 202 forms an opening 224 that is closed with an end plate226 and seals 228. A high power connector 230 extends through the endplate 226 and is connected at one end 232 to a fiber-optic cable 234. Asecond end 236 of the connector 230 is oriented to direct optical energyinto the cavity 216 and toward beam forming optics 238 mounted to theend plate 226. The beam forming optics 238 are configured to disbursereceived optical energy in a hemispherical emission pattern of uniformflux toward the photovoltaic chips 222.

Operation of this embodiment 200 is substantially similar to operationof the previously-described embodiments. Optical power is received fromthe fiber optic line 234 and emitted from the connector 230 toward beamforming optics 238. In this embodiment, however, there is a singlehemispherical array, with each PV chip 222 spaced equidistantly from thebeam forming optics 238. Thus, each PV chip 222 of the array receivesthe same amount of optical energy from the beam forming optics 238.

FIG. 11 shows yet another embodiment 300 that comprises agenerally-spherical housing 302 symmetrical about an axis 304. Thehousing includes an inlet port 306 and an outlet port 308 connected tofirst and second pipe segments 310, 312, respectively. The housing 302is formed around a beryllium oxide or similarly heat conducting yetstructurally viable material heat sink 314, which defines a sphericalcavity 316. Fluid channels 318 run through the heat sink 314 and form afluid communication path between the inlet and outlet ports 306, 308.

A high power connector 340 extends through the end plate 328 and isconnected at one end to a fiber optic cable 344. The opposing end of theconnector 340 is configured to direct optical energy toward the firstbeam forming optics 332.

A generally-spherical array of photovoltaic chips 322 is mounted to theinner surface 324 of the housing proximal to the heat sink 314. Thearray comprises first and second hemispherical arrays of chips 322 a,332 b symmetrically aligned on either side of the axis 304.

The housing 302 forms an opening 326 that is closed with an end plate328 and seals. First beam forming optics 332 are positioned in thecavity 316 and mounted to the end plate 328. Second and third beamforming optics 334, 336 are positioned in the cavity 316 proximal to itscenter. An optical splitter 338 is positioned between the second andthird beam forming optics 334, 336. The first beam forming optics 332are configured to direct received optical energy toward the opticalsplitter 338, which is configured to split and direct the receivedoptical energy to the second and third beam forming optics 334, 336. Thesecond beam forming optics 334 are configured to direct received opticalenergy to the first hemispherical array 322 a. The third beam formingoptics 336 are configured to direct received optical energy to thesecond hemispherical energy 322 b.

Operation of this embodiment 300 is substantially similar to operationof the previously-described embodiments. Optical power is received fromthe fiber optic cable 344 and emitted from the high power connector 340toward first beam forming optics 332. The first beam forming optics 332direct the received optical energy toward the splitter 338, whichdivides the received energy and directs it towards the second and thirdbeam-forming optics 334, 336. Second and third beam forming optics 334,336 direct the energy to the first and second hemispherical arrays 322a-b, respectively.

As optical energy impinges on the arrays 332 a-b, the received energy isconverted to heat and transfers to the heat sink 314. A work fluidmoving through the fluid channels 318 is heated and transfers the energyto the outlet port 308 for later use by a fluidly-connected apparatus(e.g., a Stirling engine).

The various embodiments described herein may be used singularly or inconjunction with other similar devices. Due to limits to size of powergeneration chambers (controlled by structural design and hydrostaticforce build up at great depth underwater), generating more power meansmodular power generation systems. For example, FIG. 12 shows aconfiguration that incorporates multiple instances of the embodiment 300described with reference to FIG. 11. Optical power traverses a photonicpower train 350 and is divided by a series of optical non-linear beamsplitters 352 to branch fiber lines 354 that are in opticalcommunication with the embodiments 300. The design of beam splitters 352is advantageously directed to transferring equal amounts of power to allpower generation elements 300 and also to minimizing the power lost ateach beam splitter. Stated differently, a primary photonic power trainor pipeline 350 with a series of optical non-linear fractional beamsplitters 352 transfers a standard portion of the beam from the pipeline350 to a power generation sphere, depicted as embodiment 300. Eachprimary pipeline beam splitter 352 splits off exactly the standard fluxneeded to operate an embodiment 300, e.g., a power sphere (or powercylinder), and send the rest on to the next primary pipeline beamsplitter 352. Each of these successive beam splitters 352 would besending a greater percentage of the remaining pipeline flux tosubsequent power spheres (or cylinders). In the embodiment shown in FIG.12, if only three embodiments 300 were being used, the first beamsplitter 352 would divert 33⅓% of the total power to the firstembodiment 300. The second beam splitter 352 would divert 50% of theremaining power to the second embodiment 300. The third beam splitter352 would not be needed as the pipeline 350 would end in the thirdembodiment 300.

The present disclosure includes preferred or illustrative embodiments inwhich specific power conversion modules are described. Alternativeembodiments of such devices can be used in carrying out the invention asclaimed and such alternative embodiments are limited only by the claimsthemselves. Other aspects and advantages of the present invention may beobtained from a study of this disclosure and the drawings, along withthe appended claims.

We claim:
 1. A power conversion module for use with optical energytransfer and conversion system, said module comprising: a housing havinga hemispherical configuration; an end plate connected to said housing,said end plate and housing defining a cavity; an inlet and outlet portconnected to said housing; an actively cooled high power connectorhaving one end connected to a fiber optic cable and the opposite endtraversing said end plate and extending within said cavity; beam formingoptics within said cavity in optical communication with said activelycooled high power connector, said beam forming optics configured todisburse received optical energy in a hemispherical emission pattern ofuniform flux toward said photovoltaic chips; a heat sink within saidhousing and having a plurality of fluid channels therethrough, saidplurality of fluid channels forming a fluid circulation path betweensaid inlet and outlet ports; a work fluid in fluid communication withsaid heat sink, said work fluid for transferring heat via said outletport; and an array of photovoltaic chips mounted in complementaryconfiguration to said housing within said cavity, each of saidphotovoltaic chips spaced equidistantly from said beam forming optics.2. The power conversion module of claim 1 wherein said heat sink iscomprised of beryllium oxide.
 3. A power conversion module for use withoptical energy transfer and conversion system, said module comprising: ahousing having a spherical configuration; an end plate connected to saidhousing, said end plate and housing defining a cavity; an inlet andoutlet port connected to said housing; an actively cooled high powerconnector having one end connected to a fiber optic cable and theopposite end traversing said end plate and extending within said cavity;a first beam forming optics within said cavity, said first beam formingoptics in optical communication with said actively cooled high powerconnector; a second beam forming optics within said cavity, said secondbeam forming optics in optical communication with said first beamingforming optics and configured to disburse received optical energy in ahemispherical emission pattern of uniform flux toward said photovoltaicchips; a third beam forming optics within said cavity, said third beamforming optics in optical communication with said first beam formingoptics and configured to disburse received optical energy in ahemispherical emission pattern of uniform flux toward said photovoltaicchips; an optical splitter within the center of said housing, saidoptical splitter between second and third beam forming optics and inoptical communication with said first, second and third beam formingoptics, said optical splitter configured to split and direct thereceived optical energy to said second and third beam forming optics; aheat sink within said housing and having a plurality of fluid channelstherethrough, said plurality of fluid channels forming a fluidcirculation path between said inlet and outlet ports; a work fluid influid communication with said heat sink, said work fluid fortransferring heat via said outlet port; and an array of photovoltaicchips mounted in complementary configuration to said housing within saidcavity, each of said photovoltaic chips spaced equidistantly from saidbeam forming optics.
 4. A multiple power conversion system comprising: aplurality of power conversion modules, each of said plurality of powerconversion modules comprising; a housing having a sphericalconfiguration and a plurality of channels therethrough; an end plateconnected to said housing, said end plate and housing defining a cavity;an inlet and outlet port connected to said housing; an actively cooledhigh power connector having one end connected to a fiber optic cable andthe opposite end traversing said end plate and extending within saidcavity; a first beam forming optics within said cavity, said first beamforming optics in optical communication with said actively cooled highpower connector; a second beam forming optics within said cavity, saidsecond beam forming optics in optical communication with said firstbeaming forming optics and configured to disburse received opticalenergy in a hemispherical emission pattern of uniform flux toward saidphotovoltaic chips; a third beam forming optics within said cavity, saidthird beam forming optics in optical communication with said first beamforming optics and configured to disburse received optical energy in ahemispherical emission pattern of uniform flux toward said photovoltaicchips; an optical splitter within the center of said housing, saidoptical splitter between second and third beam forming optics and inoptical communication with said first, second and third beam formingoptics, said optical splitter configured to split and direct thereceived optical energy to said second and third beam forming optics; aheat sink within said housing and having a plurality of fluid channelstherethrough, said plurality of fluid channels forming a fluidcirculation path between said inlet and outlet ports; a work fluid influid communication with said heat sink, said work fluid fortransferring heat via said outlet port; and an array of photovoltaicchips mounted in complementary configuration to said housing within saidcavity, each of said photovoltaic chips spaced equidistantly from saidbeam forming optics; a photonic power train in optical communicationwith said plurality of power conversion systems; and a plurality of beamsplitters in optical communication with said plurality of powerconversion systems, said plurality of beam splitters configured totransfer a portion of the optical energy from said photonic power trainto each of said plurality of power conversion systems.